Control of attractivity and receptivity in female red-sided garter snakes

Female red-sided garter snakes emerge from their hibernacula in the spring attractive and receptive to males. Attractivity is communicated by a pherom one released through the female's skin and is a consequence of ovarian recr udescence the previous summer. Receptivity, on the other hand, is stimulate d by ovarian estrogen secretion during emergence itself. Mating renders fem ales both unattractive and unreceptive. Another "mating" pheromone of male origin is important in making females unattractive after mating. To investi gate the role of cloacal stimulation in the loss of attractivity and recept ivity we injected a local anesthetic (lidocaine or tetracaine) in the cloac al region of females before mating. This does not prevent mating, although it blocks neural transmission of copulatory sensory stimuli. The time cours e of transition from attractive and receptive states was then observed. Fem ales treated with local anesthetic as well as control females were unattrac tive within 15 min of mating. However, when retested 2-3 and 24 h after mat ing, a significantly higher proportion of treated females regained their at tractivity, while mated control females remained unattractive. This restora tive effect was transient, though, as treated females retested 48 h after m ating were as unattractive as the controls. Both anesthetized and control f emales were unreceptive when tested following mating and did not regain rec eptivity with time. Last, the mating-induced surge in circulating concentra tions of prostaglandin was diminished in females that received a local anes thetic prior to mating. Taken together these results indicate that the loss of attractivity and receptivity following mating in the red-sided garter s nake is due to combined effects of a mating pheromone and a physiological, neurally mediated response to the sensation of stimuli associated with the act of mating. (C) 2001 Academic Press.